Closed loop heat pump systems

ABSTRACT

This disclosure relates to a closed loop heat pump system for use in multizone buildings in which the closed loop is connected through a plurality of individual zone units. The zone units are heat pumps of the type which include reversible refrigerating apparatus. The closed loop circulates a heat exchange media through the individual zone units wherein heat may be absorbed or rejected and maintains a predetermined temperature level by adding or removing heat from the heat exchange media at a temperature control center or storage vessel equipped to heat or cool the heat exchange media of the closed loop.

United States Patent [7 2] lnventor Garland L. Kendrick Arlington, Va. 21 App]. No. 871,832 [22] Filed Oct. 28, 1969 [45] Patented Sept. 28, 1971 [73] Assignee The Singer Company New York, N.Y.

[54] CLOSED LOOP HEAT PUMP SYSTEMS 2 Claims, 3 Drawing Figs.

[52] US. Cl 165/22, 165/29 [51] Int. Cl F241 3/00 [50] Field of Search 165/22, 26, 27, 29, 50, 64,140

[56] References Cited UNITED STATES PATENTS 2,715,514 8/1955 Stair 165/50 2,994,514 8/1961 Brown 3,523,575 8/1970 Olivieri Primary Examiner-Charles Sukalo Attorneys-Marshall J. Breen, Chester A. Williams, Jr. and

Harold Weinstein ABSTRACT: This disclosure relates to a closed loop heat pump system for use in multizone buildings in which the closed loop is connected through a plurality of individual zone units. The zone units are heat pumps of the type which include reversible refrigerating apparatus. The closed loop circulates a heat exchange media through the individual zone units wherein heat may be absorbed or rejected and maintains a predetermined temperature level by adding or removing heat from the heat exchange media at a temperature control center or storage vessel equipped to heat or cool the heat exchange media of the closed loop.

PATENTEU was I97! 3,608,625

( fi Garland L. Kendrick 523.1 Fig.3 JA QMJ ATTORNEY CLOSED LOOP HEAT PUMP SYSTEMS BACKGROUND OF THE INVENTION Heretofore, a closed loop heating and cooling installation was completely assembled and wired at the building site. The heating means and the cooling means were remotely located from each other, and therefore, the factory fabrication of the systems components was limited to the individual components with little or no interconnection of the system components possible prior to site assembly of the system.

SUMMARY OF THE INVENTION In accordance with the present invention, the novel closed loop heat pump system is provided with a plurality of heat pumps positioned in various zones of a building to be selectively heated or cooled thereby. The heat pump system includes a closed loop in which heat exchange medium is continuously circulated and passed through each of the heat pumps. The heat pump closed loop is connected into a temperature control center or storage vessel having integrally connected cooling means and heating means therein. A control means is mounted upon the said storage vessel operatively to control the cooling means and the heating means to maintain temperature of the heat exchange media within a predetermined range. The cooling means includes a cooling vessel extending through the storage vessel.

It is therefore an object of the present invention to provide an improved closed loop heat pump system which overcomes the prior art deficiencies; which is simple, economical and reliable; which includes a factory assembled storage vessel or temperature control center capable of being connected into the heat pump closed loop at the building site with a minimum of service wiring and piping; which uses a storage vessel or temperature control center in the heat pump closed loop in order to add or remove heat from the heat exchange media circulating in said loop; and, which uses a storage vessel or temperature control center having an integrally formed and separate cooling vessel extending therethrough.

Other objects and advantages will be apparent from the following description of one embodiment of the invention, and the novel features will be particularly pointed out hereinafter in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS This invention is illustrated in the accompanying drawings in which:

FIG. 1 is a diagrammatic view of the closed loop heat pump system of the present invention.

FIG. 2 is a side elevational view, partly in section, of the storage vessel or temperature control center of the present invention.

FIG. 3 is a diagrammatic view of one of the individual heat pump units for conditioning the zones by heating or cooling the same.

DESCRIPTION OF THE INVENTION The novel closed loop heat pump system is illustrated in FIG. 1 and includes a heat pump closed loop, designated generally 12, in which a heat exchange media such as water will be continuously circulated by a circulating pump 14 through a plurality of individual heat pumps 16 connected in the heat pump closed loop 12, which heat pumps 16 are located in the various zones of the building to be conditioned. The water temperature will be maintained within a predetermined minimum and maximum value, which may vary during the various seasons, but will usually fall somewhere within the range of 60 F. to 140 F. A storage vessel or temperature control center 18 is connected into the heat pump closed loop 12 to maintain the temperature of the water circulating therein by heating or cooling said water in a controlled manner as more fully explained hereinafter so that water discharged from the vessel 18 into the supply line 20 of the heat pump closed loop 12 will be within the desired temperature value for delivery to the individual heat pumps 16, wherein heat is either absorbed or rejected, and the water is discharged into a return line 22 carrying the water back to the storage vessel 18 to complete the loop. The individual heat pumps 16 are connected in parallel in the closed loop 12, between the supply lines 20 and the return lines 22 as shown in FIG. 1.

The heat pump closed loop 12 may have suitable valves to control the flow and permit maintenance of the system 10, as for example valves 24 and 26 on the supply side 20 and the return side 22, respectively, of each of the individual heat pumps 16 which permits removal of any individual unit without requiring a shutdown of the system 10.

The storage vessel or temperature control center 18 is factory assembled and includes a casing 28 upon which is mounted a control panel 30, and a tube type cooling heat exchanger 32 is disposed to extend through the upper portion thereof, and a plurality of electric immersion heaters 34 are fixedly mounted into the interior of the casing 28 adjacent the bottom thereof, as illustrated in FIG. 2.

The tube type heat exchanger 32 is connected into a cooling loop 36 in which cooling media, such as water, is circulated by a circulating pump 38 from one side of the heat exchanger 32 to pass to a cooling tower 40 to reduce the temperature thereof in a manner well known in the art, before returning to the opposite side of the heat exchanger 32 for recycling in the tube bundle 42 of the heat exchanger 32. The water from the closed loop 12 enters the casing side 44 of the heat exchanger 32 at the casing inlet 46 to pass in counterflow heat exchange relationship with the water in the tube bundle 42 from the cooling loop 36. Thereafter, the water from the closed loop 12 leaves the heat exchanger 32 via the aperture 48, to be discharged within the storage or heating portion of the temperature control center or vessel 18. The dotted arrows in the vessel 18 indicate the circuitous flow path of the water entering the vessel from the supply line 20 and finally being discharged at the outlet 50 of the casing 28 for recirculation in the supply line 20.

During those times when cooling of the water of the heat pump closed loop 12 is required, the cooling loop 36 and the heat exchanger 32 will be operative. However, when the temperature of the water is within the desired range or must have heat added thereto, the cooling loop 36 will be shut down and the water from the closed loop 12 will merely pass through heat exchanger 32 with substantially no effect on the temperature thereof. If heating of the water in the closed loop 12 is required, one or more of the electric immersion heaters 34 will be operative to add heat to the water in the vessel 18 so as to raise the temperature of the water to the desired level prior to it entering the supply line 20. Accordingly, the suitable electric or pneumatic controls (not shown) are mounted in the control panel 30 and are operatively connected into the heat pump system 10 to insure the maintenance of the water temperature within the desired operative range of the water circulating in the heat pump closed loop 12, by selectively calling for cooling or heating of said water within the temperature control center or vessel 18. Additionally, the control panel 30 may be equipped with other operating controls and system alarms which would indicate malfunctioning of the heat pump system 12 by the occurrence in the vessel 18 of such conditions as low water level, no water flow, low water temperature, or high water temperature.

The temperature control center 18 includes the cylindrical casing 28 in which the heat exchanger 32 is integrally formed and into which the electric immersion heaters 34 have been affixed. The control panel 30 is mounted atop the casing 28 so that all of the operating controls and system alarms are centrally located. The complete temperature control center or storage vessel 18 can be factory assembled and subsequently transported to the building site wherein it is installed into the system 10 simply by connecting the service wiring and the water piping.

Access into the interior of the casing 28 is provided by a detachable manhole cover 52.

Each of the building zones to be conditioned has at least one of the individual heat pumps 16, which may be of the type shown in FIG. 3 having reversible refrigeration apparatus, designated generally 54, and enclosed in a suitable casing 56 through which the heat pump closed loop 12 passes through in heat exchange relationship with heat exchanger 58 of the refrigeration apparatus 54. In the preferred embodiment heat exchanger 58 is a refrigerant to water type exchanger. The refrigerant apparatus 54 also includes a compressor 60, a fourway reversing valve 62, a heat exchanger 64 having coils exposed to the air circulated through the heat pump casing 56 by operation of a blower 66, a capillary restrictor tube 68 and a closed refrigerant circulating loop 70.

The conditioning cycle of the heat pump 16 can be automatically controlled responsive a suitable device, such as a wall thermostat (not shown) which will set the position of the valve 62 to dictate the flow path of the refrigerant in the loop 70, thus obtaining heating or cooling. The solid line position of valve 62 shown in FIG. 3 corresponds to the heating cycle. The cooling cycle position of the valve 62 is indicated by the dotted lines whereby the valve would be rotated 90. in the heating cycle, the compressor 60 pumps hot compressed refrigerant gas to the air side heat exchanger 64 wherein the refrigerant gas will be condensed to a liquid by giving up heat to the air being drawn thereover by the blower 66. Thus, the air is warmed in the heat pump and returned to the zone. The liquid refrigerant passes through the capillary restrictor tube 68 causing a pressure drop therein and expands into a gas within the coaxial refrigerant to water exchanger 58, wherein heat is absorbed from the water circulating in the closed loop 12. The refrigerant gas now passes through the solid line path of the valve 62 to the suction of the compressor 60 wherein the cycle is repeated.

When cooling is required, the valve 62 will assume the dotted line position so that the compressor will pump hot compressed refrigerant gas to the coaxial refrigerant to water exchanger 58, wherein the gas is condensed to a liquid by giving up heat to the water circulating in the closed loop 12 therein. The liquid refrigerant passes through a capillary restricted tube 68 causing a pressure drop and expands into a gas within the air side heat exchanger 64 by picking up heat from the warmer zone air returned to the heat pump 16 by the action of blower 66. The air is cooled down and discharged from the heat pump 16 into the zone. The refrigerant gas passes from the exchanger 64 through the indicated dotted line connection of valve 62 to the suction of the compressor wherein the cycle is repeated.

For summer operation, the heat pumps 16 will add heat to the water circulating in the closed loop 12 so that the water returning to the vessel 18 will be cooled in the heat exchanger 32 by passing in counterflow heat exchange relationship with the water circulating in the cooling loop 36. During winter operation, heat pumps 16 will substantially be operated to heat the various zones taking supplemental heat from the water circulating in the closed loop 12, whereby said water upon return to the vessel 18, can be reheated by operation of the electric immersion heaters.

For spring and fall operation, of the heat pump system 10, some of the heat pumps may be operated on the heating cycle and some may be operated on the cooling cycle, so that heat will both be added and given up by the circulating water of the closed loop 12. The temperature of the circulating water in the closed loop 12 will be controlled at the vessel 18 so that if the net effect of the individual heat pumps 16 changes the temperature of the circulating water above or below that desired, the cooling or heating means, respectively, will be called into operation so as to maintain the desired circulating temperature of the water in the closed loop 12.

It will be understood that various changes in the details, materials, arrangements of parts and operating conditions which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principles and scope of the invention.

What is claimed is:

1. In a heat pump system having a plurality of heat pumps positioned in various zones to be selectively heated or cooled, the combination of:

a. a heat pump closed loop having a heat exchange media continuously circulating therein and passing through each of the heat pumps,

b. a storage vessel connected in the heat pump closed loop,

c. the storage vessel having an upper portion therein to receive the heat exchange media from the heat pump closed loop and a lower portion therein, defining a reservoir from which the heat exchange media is returned to the heat pump closed loop,

(1. a cooling vessel of the tube and shell type formed integrally within the upper portion of the storage vessel,

e. a cooling water loop for circulating cooling water is formed in the heat pump system separate from the heat pump closed loop,

f. the cooling water loop includes the cooling vessel, a cooling tower, a circulating pump and connecting conduit means therebetween,

g. the tubes of the cooling vessel having the cooling water pass therethrough,

h. the shell of the cooling vessel having the heat exchange media pass therethrough in noncontacting heat exchange relationship with the cooling water in said tubes,

i. heating means including a plurality of immersed electric heating elements connected within the lower reservoir portion of the storage vessel remote from the cooling vessel, and

j. control means mounted upon the storage vessel operatively to control the cooling means and the heating means to maintain the temperature of the heat exchange media within a predetermined range by selectively circulating the cooling water through the cooling vessel, or actuating one or more of the heating elements.

2. The combination claimed in claim 1 wherein:

a. the cooling vessel has a casing with a header at each end thereof disposed externally of the storage vessel and each of the headers connect into the cooling water loop,

b. the tubes of the cooling vessel connecting one header with the other header,

c. the casing has a shell through which passes the heat exchange media,

d. the shell has an external connection with the heat pump closed loop to receive heat exchange media in counterflow relationship with the cooling water passing within the tubes, and

e. the shell has an aperture formed at the other end thereof within the upper portion of the storage vessel to discharge the heat exchange media into said upper portion. 

1. In a heat pump system having a plurality of heat pumps positioned in various zones to be selectively heated or cooled, the combination of: a. a heat pump closed loop having a heat exchange media continuously circulating therein and passing through each of the heat pumps, b. a storage vessel connected in the heat pump closed loop, c. the storage vessel having an upper portion therein to receive the heat exchange media from the heat pump closed loop and a lower portion therein, defining a reservoir from which the heat exchange media is returned to the heat pump closed loop, d. a cooling vessel of the tube and shell type formed integrally within the upper portion of the storage vessel, e. a cooling water loop for circulating cooling water is formed in the heat pump system separate from the heat pump closed loop, f. the cooling water loop includes the cooling vessel, a cooling tower, a circulating pump and connecting conduit means therebetween, g. the tubes of the cooling vessel having the cooling water pass therethrough, h. the shell of the cooling vessel having the heat exchange media pass therethrough in noncontacting heat exchange relationship with the cooling water in said tubes, i. heating means including a plurality of immersed electric heating elements connected within the lower reservoir portion of the storage vessel remote from the cooling vessel, and j. control means mounted upon the storage vessel operatively to control the cooling means and the heating means to maintain the temperature of the heat exchange media within a predetermined range by selectively circulating the cooling water through the cooling vessel, or actuating one or more of the heating elements.
 2. The combination claimed in claim 1 wherein: a. the cooling vessel has a casing with a header at each end thereof disposed externally of the storage vessel and each of the headers connect into the cooling water loop, b. the tubes of the cooling vessel connecting one header with the other header, c. the casing has a shell through which passes the heat exchange media, d. the shell has an external connection with the heat pump closed loop to receive heat exchange media in counterflow relationship with the cooling water passing within the tubes, and e. the shell has an aperture formed at the other end thereof within the upper portion of the storage vessel to discharge the heat exchange media into said upper portion. 